(a) Field
Embodiments of the present invention relate to a display device and a method of driving the same. More particularly, the present invention relates to an active matrix display device and a method of driving the same.
(b) Description of the Related Art
An organic light emitting diode (OLED) display uses OLEDs in which luminance is controlled by a current or a voltage. An OLED includes a positive electrode layer and a negative electrode layer that form an electric field, and an organic light emitting material that emits light due to the electric field.
In general, OLEDs are classified into either a passive matrix OLED (PMOLED) or an active matrix OLED (AMOLED) based on the driving method of the OLED.
AMOLEDs that can selectively lighten in every unit pixel are advantageous from the viewpoint of resolution, contrast, and operation speed, and are thus a widely used type of OLED. A frame period for an AMOLED includes a scan period that writes image data and a light emitting period that emits light based on the written image data.
In a display panel, a plurality of scan lines to which a scan signal is applied and a plurality of data lines to which a data signal is applied are arranged, and at an intersection of the scan line and the data line, a pixel is formed. The display panel also includes a power source wire entirely formed in over the display panel. The power source wire is applied with a power supply voltage to cause the OLED to emit light.
During a scan period, a scan signal of a gate-on voltage is sequentially applied to the plurality of scan lines, and a data signal is applied to the plurality of data lines to correspond to a scan signal of a gate-on voltage, and thus image data is written at a plurality of pixels. Data signals are applied to the plurality of data lines with a controlled slew rate (i.e., a controlled rise rate of the voltage). Cases may occur, however, in which a data signal is applied to a plurality of data lines without being substantially controlled by the slew rate. In such a case, the voltage of the data line may be rapidly changed. Because wire resistance exists at the power supply wire, as a result of parasitic capacitance between the data line and power supply wire, the power supply voltage may be then be rapidly changed. A rapid change in the power supply voltage may have a harmful influence on the image quality. Furthermore, in a touch screen in which a touch sensor is formed adjacent to the display panel, as the result of such instantaneous rapid change in the power supply voltage, coupling noise occurs between a wire of the touch sensor and the power supply wire, and as a result of such coupling noise, a touch detection error may occur.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.